Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of a first image in a sequence for a display screen or portion thereof with transitional graphical user interface according to our design;

FIG. 2 is a front view showing a second image thereof;

FIG. 3 is a front view showing a third image thereof;

FIG. 4 is a front view showing a fourth image thereof;

FIG. 5 is a front view showing a fifth image thereof;

FIG. 6 is a front view showing a sixth image thereof;

FIG. 7 is a front view showing a seventh image thereof;

FIG. 8 is a front view showing an eighth image thereof;

FIG. 9 is a front view showing a ninth image thereof; and,

FIG. 10 is a front view showing a tenth image thereof.

The appearance of the transitional image sequentially transitions between the images shown in FIGS. 1-10. The process or period in which one image transitions to another image forms no part of the claimed design.

The broken lines showing portions of the display screen and all other broken lines showing portions of the graphical user interface illustrate portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 